Any item in the game can be enchanted with any enchanted book in the game by simply combining them in the anvil. But conflicting enchants still can't be put together. The exp cost is also bugged. It goes up to 16385, after that when you try to combine another book it doesn't show you the any cost message, and then the cost resets itself.
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I guess so.
Thank you for your report!
We're tracking this issue in MC-95555, so this ticket is being resolved and linked as a duplicate.
That ticket has already been resolved as working as intended, which means this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.
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Duplicate of MC-95555?